Executive control mediates memory's association with change in instrumental activities of daily living: the Freedom House Study

OBJECTIVES: To assess the relative independent contribution of changes in executive control function (ECF) and memory to changes in functional status. DESIGN: Three-year longitudinal cohort study. SETTING: A comprehensive care retirement community. PARTICIPANTS: Five hundred forty-seven noninstitutionalized people aged 70 and older. MEASUREMENTS: The California Verbal Learning Test (CVLT) and Executive Interview (EXIT25). Functional status was assessed using instrumental activities of daily living (IADLs). Latent growth curves of CVLT, EXIT25, and IADLs were modeled. The rate of change in IADLs (adjusted for baseline IADLs and cognition) was regressed on the rate of change in each cognitive measure. Models were also adjusted for baseline age, level of care, and comorbid illnesses. RESULTS: There was significant variability around the baseline means and slopes for all variables. The rate of change in EXIT25 was independently correlated with the rate of change in IADLs (correlation coefficient (r)=-0.52, P<.001). This remained significant after adjusting for baseline EXIT25 scores, IADLs, age, comorbid disease, and level of care. The EXIT25's effect on the rate of change in IADLs was stronger than those of age, baseline IADLs, comorbid disease, or level of care. The rate of change in CVLT scores was not significantly associated with the rate of change in IADLs. CONCLUSION: ECF is a strong, significant, and independent correlate of functional status in normal aging. In contrast, decline in memory, as measured using the CVLT, has no independent association with the rate of change in functional status. This suggests that amnestic mild cognitive impairment can be associated with dementia only though the subsequent or comorbid development of ECF impairment.     

Angiotensinogen gene T235 variant: a marker for the development of persistent microalbuminuria in children and adolescents with type 1 diabetes mellitus

AIM: We examined genetic polymorphisms in the renin-angiotensin system (RAS) coding for angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) for angiotensinogen (AGT) M235T and angiotensin II receptor type 1 (AGTR1) A1166C as predictors for the development of microalbuminuria (MA) in children with type 1 diabetes mellitus (T1DM). METHODS: Four hundred fifty-three (215 males, 238 females) T1DM children [median (interquartile range): age, 16.7 years (13.9-18.3); diabetes duration, 6.9 years (3.3-10.8); age at diagnosis, 9.1 years (5.8-11.8)] were followed prospectively from diagnosis until the development of MA (two of three consecutive overnight urine samples with albumin excretion rates of > or =20 and <200 microg/min). Kaplan-Meier survival curves and Cox proportional multivariate model estimated the probability of developing MA and the relative risk for MA among different variables. RESULTS: MA developed in 41 (9.1%) subjects. The frequencies of genotypes were as follows: ACE-II 112 (25%), ACE-ID 221 (49%), and ACE-DD 117 (26%) (n=450); AGT-MM 144 (32%), AGT-MT 231 (51%), and AGT-TT 77 (17%) (n=452); AGTR1-AA 211 (47%), AGTR1-AC 204 (45%), and AGTR1-CC 37 (8%) (n=452). The cumulative risk for the development of MA was higher in ACE-DD versus ACE-ID/II groups (log-rank test, P=.05), and a trend was noticed when AGT-TT was compared to AGT-MT/MM groups (log-rank test, P=.08). AGT-TT polymorphism conferred a fourfold increased risk for MA compared to AGT-MM/MT (hazard ratio=3.8; 95% confidence interval=1.43-10.3; P=.008). INTERPRETATION: Our findings suggest that RAS gene polymorphism at AGT M235T is a strong predictor for early MA in young T1DM subjects.     

Development and evaluation of a gamma-interferon assay for tuberculosis in badgers (Meles meles)

In this paper we report the development of a sensitive and specific assay for the detection of tuberculosis (TB) in European badgers (Meles meles), based on the stimulation of lymphocytes in whole-blood culture and the subsequent detection of gamma-interferon (IFNgamma) by sandwich ELISA. The comparative levels of IFNgamma produced to bovine and avian tuberculin (B-A) was used as the basis of determining the TB status of badgers, resulting in a more sensitive test than that based on the defined Mycobacterium bovis antigens ESAT6 and CFP10. The assay was evaluated using 235 badgers. The IFNgamma EIA (enzyme immunoassay) based on a monoclonal pair (mEIA) was more sensitive than one using a rabbit polyclonal antiserum (pEIA). At a specificity of 93.6%, the mEIA was 80.9% sensitive, compared to a sensitivity of 74.5% for the pEIA. At the same specificity as the EIA, the current serological ELISA test for TB in badgers (Brock test) had a sensitivity of 48.9%. Only one of the culture positive badgers missed by the mEIA was correctly diagnosed by the Brock test, suggesting that the combination of both a T-cell and serological test has little diagnostic advantage.     

Gene variants influencing measures of inflammation or predisposing to autoimmune and inflammatory diseases are not associated with the risk of type 2 diabetes

Aims/hypothesis  There are strong associations between measures of inflammation and type 2 diabetes, but the causal directions of these associations are not known. We tested the hypothesis that common gene variants known to alter circulating levels of inflammatory proteins, or known to alter autoimmune-related disease risk, influence type 2 diabetes risk. Methods  We selected 46 variants: (1) eight variants known to alter circulating levels of inflammatory proteins, including those in the IL18, IL1RN, IL6R, MIF, PAI1 (also known as SERPINE1) and CRP genes; and (2) 38 variants known to predispose to autoimmune diseases, including type 1 diabetes. We tested the associations of these variants with type 2 diabetes using a meta-analysis of 4,107 cases and 5,187 controls from the Wellcome Trust Case Control Consortium, the Diabetes Genetics Initiative, and the Finland–United States Investigation of NIDDM studies. We followed up associated variants (p < 0.01) in a further set of 3,125 cases and 3,596 controls from the UK. Results  We found no evidence that inflammatory or autoimmune disease variants are associated with type 2 diabetes (at p ≤ 0.01). The OR observed between the variant altering IL-18 levels, rs2250417, and type 2 diabetes (OR 1.00 [95% CI 0.99–1.03]), is much lower than that expected given (1) the effect of the variant on IL-18 levels (0.28 SDs per allele); and (2) estimates, based on other studies, of the correlation between IL-18 levels and type 2 diabetes risk (approximate OR 1.15 [95% CI 1.09–1.21] per 0.28 SD increase in IL-18 levels). Conclusions/interpretation  Our study provided no evidence that variants known to alter measures of inflammation, autoimmune or inflammatory disease risk, including type 1 diabetes, alter type 2 diabetes risk. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Variable stoichiometry of the TatA component of the twin-arginine protein transport system observed by in vivo single-molecule imaging

The twin-arginine translocation (Tat) system transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of plant chloroplasts. The essential components of the Tat pathway are the membrane proteins TatA, TatB, and TatC. TatA is thought to form the protein translocating element of the Tat system. Current models for Tat transport make predictions about the oligomeric state of TatA and whether, and how, this state changes during the transport cycle. We determined the oligomeric state of TatA directly at native levels of expression in living cells by photophysical analysis of individual yellow fluorescent protein-labeled TatA complexes. TatA forms complexes exhibiting a broad range of stoichiometries with an average of approximately 25 TatA subunits per complex. Fourier analysis of the stoichiometry distribution suggests the complexes are assembled from tetramer units. Modeling the diffusion behavior of the complexes suggests that TatA protomers associate as a ring and not a bundle. Each cell contains approximately 15 mobile TatA complexes and a pool of approximately 100 TatA molecules in a more disperse state in the membrane. Dissipation of the protonmotive force that drives Tat transport has no affect on TatA complex stoichiometry. TatA complexes do not form in cells lacking TatBC, suggesting that TatBC controls the oligomeric state of TatA. Our data support the TatA polymerization model for the mechanism of Tat transport.     

Cognitive effects of treating obstructive sleep apnea in Alzheimer's disease: a randomized controlled study

OBJECTIVES: To examine whether treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) in patients with Alzheimer's disease (AD) results in better cognitive function. DESIGN: Randomized double‐blind placebo‐controlled trial. Participants were randomized to therapeutic CPAP for 6 weeks or placebo CPAP for 3 weeks followed by therapeutic CPAP for 3 weeks. SETTING: General clinical research center. PARTICIPANTS: Fifty‐two men and women with mild to moderate AD and OSA. INTERVENTION: CPAP. MEASUREMENTS: A complete neuropsychological test battery was administered before treatment and at 3 and at 6 weeks. RESULTS: A comparison of subjects randomized to 3 weeks of therapeutic versus placebo CPAP suggested no significant improvements in cognition. A comparison of pre‐ and posttreatment neuropsychological test scores after 3 weeks of therapeutic CPAP in both groups showed a significant improvement in cognition. The study was underpowered to make definitive statements about improvements within specific cognitive constructs, although exploratory post hoc examination of change scores for individual tests suggested improvements in episodic verbal learning and memory and some aspects of executive functioning such as cognitive flexibility and mental processing speed. CONCLUSION: OSA may aggravate cognitive dysfunction in dementia and thus may be a reversible cause of cognitive loss in patients with AD. OSA treatment seems to improve some cognitive functioning. Clinicians who care for patients with AD should consider implementing CPAP treatment when OSA is present.     

Treatment of rheumatoid arthritis with methotrexate and hydroxychloroquine,methotrexate and sulfasalazine,or a combination of the three medications: Results of a two‐year,randomized, double‐blind,placebo‐controlled trial

Objective

To compare the efficacy of combination therapy with methotrexate (MTX) and hydroxychloroquine (HCQ), MTX and sulfasalazine (SSZ), and MTX, HCQ, and SSZ in patients with rheumatoid arthritis (RA).

Methods

RA patients (n = 171) who had not previously been treated with combinations of the study medications were randomized to receive 1 of the 3 treatment combinations in this 2‐year, double‐blind, placebo‐controlled protocol. HCQ was given at a dosage of 200 mg twice a day. The dosage of MTX was accelerated from 7.5 mg/week to 17.5 mg/week in all patients who were not in remission. Similarly, the dosage of SSZ was escalated from 500 mg twice a day to 1 gm twice a day in patients who were not in remission. The primary end point of the study was the percentage of patients who had a 20% response to therapy according to the American College of Rheumatology (ACR) criteria at 2 years.

Results

Intent‐to‐treat analysis revealed that patients receiving the triple combination responded best, with 78% achieving an ACR 20% response at 2 years, compared with 60% of those treated with MTX and HCQ (P = 0.05) and 49% of those treated with MTX and SSZ (P = 0.002). Similar trends were seen for the ACR 50% response, with 55%, 40%, and 29% of patients in the 3 treatment groups, respectively, achieving these results at 2 years (P = 0.005 for the triple combination group versus the MTX and SSZ group). All combination treatments were well‐tolerated. Fourteen patients (evenly distributed among the 3 groups) withdrew from the protocol because of symptoms that were potentially related to the study medication.

Conclusion

The triple combination of MTX, SSZ, and HCQ is well‐tolerated, and its efficacy is superior to that of the double combination of MTX and SSZ and is marginally superior to that of the double combination of MTX and HCQ.

     

Punctuated evolution of mitochondrial gene content: high and variable rates of mitochondrial gene loss and transfer to the nucleus during angiosperm evolution

To study the tempo and pattern of mitochondrial gene loss in plants, DNAs from 280 genera of flowering plants were surveyed for the presence or absence of 40 mitochondrial protein genes by Southern blot hybridization. All 14 ribosomal protein genes and both sdh genes have been lost from the mitochondrial genome many times (6 to 42) during angiosperm evolution, whereas only two losses were detected among the other 24 genes. The gene losses have a very patchy phylogenetic distribution, with periods of stasis followed by bursts of loss in certain lineages. Most of the oldest groups of angiosperms are still mired in a prolonged stasis in mitochondrial gene content, containing nearly the same set of genes as their algal ancestors more than a billion years ago. In sharp contrast, other plants have rapidly lost many or all of their 16 mitochondrial ribosomal protein and sdh genes, thereby converging on a reduced gene content more like that of an animal or fungus than a typical plant. In these and many lineages with more modest numbers of losses, the rate of ribosomal protein and sdh gene loss exceeds, sometimes greatly, the rate of mitochondrial synonymous substitutions. Most of these mitochondrial gene losses are probably the consequence of gene transfer to the nucleus; thus, rates of functional gene transfer also may vary dramatically in angiosperms.     

Inhaled hydrogen sulfide induces suspended animation, but does not alter the inflammatory response after blunt chest trauma

The treatment of acute lung injury and septic complications after blunt chest trauma remains a challenge. Inhaled hydrogen sulfide (H?S) may cause a hibernation-like metabolic state, which refers to an attenuated systemic inflammatory response. Therefore, we tested the hypothesis that inhaled H?S-induced suspended animation may attenuate the inflammation after pulmonary contusion. Male Sprague-Dawley rats were subjected to blunt chest trauma (blast wave) or sham procedure and subsequently exposed to a continuous flow of H?S (100 ppm) or control gas for 6 h. Body temperature and activity were measured by an implanted transmitter. At 6, 24, or 48 h after trauma, animals were killed, and the cellular contents of bronchoalveolar lavage (BAL) as well as cytokine concentrations in BAL, plasma, and culture supernatants of blood mononuclear cells, Kupffer cells, splenic macrophages, and splenocytes were determined. Hydrogen sulfide inhalation caused a significant reduction in body temperature and activity. The trauma-induced increase in alveolar macrophage counts was abrogated 48 h after trauma when animals received H?S, whereas the trauma-induced increase in neutrophil counts was unaltered. Furthermore, H?S inhalation partially attenuated the mediator release in BAL and culture supernatants of Kupffer cells as well as splenic cells; it altered plasma cytokine concentrations but did not affect the trauma-induced changes in mononuclear cell culture supernatants. These findings indicate that inhaled H?S induced a reduced metabolic expenditure and partially attenuated inflammation after trauma. Nevertheless, in contrast to hypoxic- or pathogen-induced lung injury, H?S treatment appears to have no protective effect after blunt chest trauma.